From patchwork Fri Oct 27 15:06:49 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Michael, Alice" X-Patchwork-Id: 831537 X-Patchwork-Delegate: jeffrey.t.kirsher@intel.com Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=osuosl.org (client-ip=140.211.166.137; helo=fraxinus.osuosl.org; envelope-from=intel-wired-lan-bounces@osuosl.org; receiver=) Received: from fraxinus.osuosl.org (smtp4.osuosl.org [140.211.166.137]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3yP05t1ks7z9t4X for ; Sat, 28 Oct 2017 10:12:50 +1100 (AEDT) Received: from localhost (localhost [127.0.0.1]) by fraxinus.osuosl.org (Postfix) with ESMTP id C792F891E7; Fri, 27 Oct 2017 23:12:48 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from fraxinus.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id cgqlFudpWzQc; Fri, 27 Oct 2017 23:12:48 +0000 (UTC) Received: from ash.osuosl.org (ash.osuosl.org [140.211.166.34]) by fraxinus.osuosl.org (Postfix) with ESMTP id 058D8891B0; Fri, 27 Oct 2017 23:12:48 +0000 (UTC) X-Original-To: intel-wired-lan@lists.osuosl.org Delivered-To: intel-wired-lan@lists.osuosl.org Received: from whitealder.osuosl.org (smtp1.osuosl.org [140.211.166.138]) by ash.osuosl.org (Postfix) with ESMTP id D8AD91C1F24 for ; Fri, 27 Oct 2017 23:12:44 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by whitealder.osuosl.org (Postfix) with ESMTP id D1BDF8A0D6 for ; Fri, 27 Oct 2017 23:12:44 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from whitealder.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id LP-YwJbbtLi8 for ; Fri, 27 Oct 2017 23:12:43 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by whitealder.osuosl.org (Postfix) with ESMTPS id 2F7968A0AA for ; Fri, 27 Oct 2017 23:12:43 +0000 (UTC) Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 27 Oct 2017 16:12:42 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos; i="5.44,306,1505804400"; d="scan'208"; a="1236400554" Received: from unknown (HELO localhost.jf.intel.com) ([10.166.16.121]) by fmsmga002.fm.intel.com with ESMTP; 27 Oct 2017 16:12:41 -0700 From: Alice Michael To: alice.michael@intel.com, intel-wired-lan@lists.osuosl.org Date: Fri, 27 Oct 2017 11:06:49 -0400 Message-Id: <20171027150656.68250-2-alice.michael@intel.com> X-Mailer: git-send-email 2.9.5 In-Reply-To: <20171027150656.68250-1-alice.michael@intel.com> References: <20171027150656.68250-1-alice.michael@intel.com> Subject: [Intel-wired-lan] [next PATCH S81-V3 2/9] i40evf: don't rely on netif_running() outside rtnl_lock() X-BeenThere: intel-wired-lan@osuosl.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Intel Wired Ethernet Linux Kernel Driver Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: intel-wired-lan-bounces@osuosl.org Sender: "Intel-wired-lan" From: Jacob Keller In i40evf_reset_task we use netif_running() to determine whether or not the device is currently up. This allows us to properly free queue memory and shut down things before we request the hardware reset. It turns out that we cannot be guaranteed of netif_running() returning false until the device is fully up, as the kernel core code sets __LINK_STATE_START prior to calling .ndo_open. Since we're not holding the rtnl_lock(), it's possible that the driver's i40evf_open handler function is currently being called while we're resetting. We can't simply hold the rtnl_lock() while checking netif_running() as this could cause a deadlock with the i40evf_open() function. Additionally, we can't avoid the deadlock by holding the rtnl_lock() over the whole reset path, as this essentially serializes all resets, and can cause massive delays if we have multiple VFs on a system. Instead, lets just check our own internal state __I40EVF_RUNNING state field. This allows us to ensure that the state is correct and is only set after we've finished bringing the device up. Without this change we might free data structures about device queues and other memory before they've been fully allocated. Signed-off-by: Jacob Keller Tested-by: Andrew Bowers --- drivers/net/ethernet/intel/i40evf/i40evf_main.c | 20 +++++++++++++++++--- 1 file changed, 17 insertions(+), 3 deletions(-) diff --git a/drivers/net/ethernet/intel/i40evf/i40evf_main.c b/drivers/net/ethernet/intel/i40evf/i40evf_main.c index ca2ebdb..320408f 100644 --- a/drivers/net/ethernet/intel/i40evf/i40evf_main.c +++ b/drivers/net/ethernet/intel/i40evf/i40evf_main.c @@ -1796,7 +1796,11 @@ static void i40evf_disable_vf(struct i40evf_adapter *adapter) adapter->flags |= I40EVF_FLAG_PF_COMMS_FAILED; - if (netif_running(adapter->netdev)) { + /* We don't use netif_running() because it may be true prior to + * ndo_open() returning, so we can't assume it means all our open + * tasks have finished, since we're not holding the rtnl_lock here. + */ + if (adapter->state == __I40EVF_RUNNING) { set_bit(__I40E_VSI_DOWN, adapter->vsi.state); netif_carrier_off(adapter->netdev); netif_tx_disable(adapter->netdev); @@ -1854,6 +1858,7 @@ static void i40evf_reset_task(struct work_struct *work) struct i40evf_mac_filter *f; u32 reg_val; int i = 0, err; + bool running; while (test_and_set_bit(__I40EVF_IN_CLIENT_TASK, &adapter->crit_section)) @@ -1913,7 +1918,13 @@ static void i40evf_reset_task(struct work_struct *work) } continue_reset: - if (netif_running(netdev)) { + /* We don't use netif_running() because it may be true prior to + * ndo_open() returning, so we can't assume it means all our open + * tasks have finished, since we're not holding the rtnl_lock here. + */ + running = (adapter->state == __I40EVF_RUNNING); + + if (running) { netif_carrier_off(netdev); netif_tx_stop_all_queues(netdev); adapter->link_up = false; @@ -1964,7 +1975,10 @@ static void i40evf_reset_task(struct work_struct *work) mod_timer(&adapter->watchdog_timer, jiffies + 2); - if (netif_running(adapter->netdev)) { + /* We were running when the reset started, so we need to restore some + * state here. + */ + if (running) { /* allocate transmit descriptors */ err = i40evf_setup_all_tx_resources(adapter); if (err)